Auto regenerates the cache on file change so no need for restart of server or manual action.

Run pre/post manipulation on the files

Use regex to match user agent so you can serve different modified versions of your packed assets based on the requesting browser.

Supplies a reference to the modified dates for all groups through assetManager().cacheTimestamps[groupName] as well as md5 hashes assetManager().cacheHashes[groupName] which can be used for cache invalidation in templates.

There are hooks in the assetManager that allow you to programmaticly alter the source of the files you are grouping.
This can be handy for being able to use custom CSS types in the assetManager or fixing stuff like vendor prefixes in a general fashion.